Clamping mechanism



June 8, 1937. c. M. ANDREWS CLAMPING MECHANISM 2 Sheets-Sheet l Filed April 4, 1955 June 8, 1937. I c, ANDREWS 2,083,419

CLAMP ING MECHANI S M Filed April 4, 1935 v 2 Sheets-Sheet 2 Patented June 8, 19 37 UNlTED srArEs se ne ATENT oer-is Application April 4, 1935, Serial No. 14,609

7 Claims.

My invention relates to a clamping mechanism, one of the objects being to provide a device for clamping to a support, with equal pressure and by a single operation, a plurality of castings or the like which have varying dimensions.

Another object of my invention is to produce a hydraulically actuated mechanism for the purpose stated.

Other objects of my invention will become apparent from the following description of a single embodiment taken in connection with the accompanying drawings in which Figure 1 is a top view of my clamping mechanism as used on a milling machine; Figure 2 is a side View of the structure shown in Figure 1; Figure 3 is a partial cross-scctional view on the line 33 of Figure 1,

showing a fluid motor and clamp; Figure 4 is a cross-sectional view on the line 44 of Figure 1,

showing one of the compressors.

In the drawings I have shown my invention applied to a milling macfiiine for clamping a plurality of castings of varying size toa supporting table for milling operations, but it is to be understood that the invention may be equally as well applied to other machines wherein it is desired to clamp a plurality of articles of varying size to a support.

Referring to the drawings, the table I of the milling machine carries two batteries of my novel clamps. Figures 1 and 2 show only one of the batteries, there being a duplicate battery positioned on the opposite side of the table. Only one battery of clamps will be described in detail.

The table is adapted to be pivotally mounted upon a post 2 carried by the milling machine base,

and is provided with a pair of bearings 3 for a rotatable shaft 4. This shaft is irregular in crosssection and the bearings 3 are received in annular grooves in the shaft, as shown in Figure 2. The shaft 4 carries a plurality of fluid motors, each comprising a cylinder 5 and a pistont. A piston rod 1 extends through an opening in the base of each cylinder, and a spring 8 surrounds the piston rod for maintaining the piston in retracted position. A suitable packing cup 9 prevents leakage between the piston and the cylinder wall. The open end of each cylinder is closed by a screw plug 1 ii.

The table I has pivoted thereon adjacent the shaft a plurality of clamping members ii, there being a clamping member for each cylinder and piston combination carried by the shaft. The clamping member is formed with an extended portion II which is adapted to be engagedby the piston rod 1 when the clamp is to be operated.

Eachclampingmember is also provided with another extended portion l2 for co-operation with the element to be clamped, such element in this instance being shown as a cylinder casting E3. The table I is provided with suitable supports I4 for receiving the castings, these supports taking the form of upstanding posts which are received in the bore of the cylinder casting. The por-- tion of the cylinder casting which is to be milled is the fiat integral extension l5.

The rotatable shaft d also carries two com pressors 16, each comprising a cylinder ill and a co -operating piston l3 having a suitable packing cup is. The pistons of the compressors are adapted to be actuated byset screws 20 thread edly co-operating with the closure plates 2| of the cylinders; The compressors I6 are in communication witheach other andwith each of the fluid motors by passages 22 extending through the shaft.

The table also has fixed thereto a pair of plates 23 which form bearings for the ends of shaft 5. One end of the shaft has formed therein a passage it by means of which the system may be filled witha suitable liquid, this passage being closed bya plug 25. The other end or" the shaft has formed therein a passage 26, which is controlledby a screw plug 21', the purpose of which is topermit bleeding of the system so that any therein may be eliminated when is filled.

Shaft t is cut away as shown at 28 in order to permit the portions Il of the clamping members i l to swing downward when the shaft l is rotated through a tire-determined angle. Thus the clamping members may be moved clear of the cylinder castings to permit the castings to be readily removed from their supports.

In the operation of my clamping device, the system is filled with .a suitable liquid and all the air therein eliminated'f'When the device is in its inoperative position, the shaft 4 will be in a position wherein the piston rods 1 are out of engagementwith the clamping members l i and the set screws for the compressors are backed oif from the pistons l8. Byswinging the clamping members away from the supports M, thev cylinder castings, which are of varying dimensions; may be readily placed on their supports Hi. The clamping membersmay now be moved to engage the casting and then the shaft -'l rotated in a counter-clockwise direction and to a position where the piston rods 1 are beneath the clamping portions H The set screws or the compressors are now screwed down, thereby forcing liquid the system u under pressure into the cylinders 5, and causing the pistons 6 and the piston rods connected thereto to exert pressures onthe clamping members and clamp the castings l3 rigidly to their supports. Regardless of the variations in the dimensions of the cylinder castings, each casting will be clamped to the support by an equal pressure. With the cylinder castings clamped in this position, the table I is now swung about post 2 and through 180 degrees and rigidly fastened to the base of the milling machine by means of the openings 29, which are'adapted to receive suitable spring pressed pins (not shown). I The cut ting elements of the milling machine may now be brought across the cylinder castings, thereby milling the surfaces M on the castings.

To remove the castings from the clamping machines, the liquid under pressure in the fluid motorsis released by unscrewing the set screws of the compressors. The fluid motor pistons 6 will be moved to their retracted position by the springs 8. The shaft 4 is now free to be rotated in a clockwise direction (shown by the arrow in Figure 3) thus moving the piston rods from beneath the clamping portions H The clamping members are now free to be swung away from the castings, whereby the castings can be readily removed from their supports.

Since the table I is provided with two batteries of clamping members, the castings which are held. by the opposite battery of clamps (not shown) may be removed and unmilled castings substituted therefor while the milling operation is being performed on the castings held by the first battery of clamps. I V

The two compressors I6 may, if desired, be replaced by a single compressor of larger size.

However, by employing two compressors, the size of the shaft! can be heldto a minimum. When two compressors are, used one may be employed .to initially displace the fluid in the system and bring the clamps into contact with the castings,

1. In a machine for clamping a plurality of members to a support, a movable clamp for cooperating with each member to be clamped, a rotatable member, a plurality of fluid operated vmotors carried by the rotatable member, each adapted to operate a clamp, a fluid compressor carried by the rotatable member and operatively connected with each fluid motor, and means for operating said compressor to apply an equal presously.

and a rotatable member for carrying the motor and the compressor as a unit, said motor being adapted. to be operatively disconnected from said clamp by the rotation of said rotatable member whereby said clamp may be piv'otally moved to permit insertion and removal of the member to be clamped.

3. In a machine, a support, a battery of pivoted clamps on the support for clamping a plurality of members to the support, a member movable on the support, a plurality of fluid motors carried by the movable member, and means comprising a fluid compressor mounted on the movable member and in communication with each motor to apply equal pressure to each clamp, said fluid motors being operably disconnected from the clamps by movement of the movable member.

4. ,In a clamping machine, a battery of clamps, a rotatable member, a fluid motor for each clamp and carried by the rotatable member, a fluid compressor carried by the rotatable member, conduits in said rotatable member for connecting the compressor with each motor and means for disconnecting each motor from its clamp by rotating the rotatable member through a pre-de- I termined angle.

5. In a clamping mechanism for clamping a plurality of members to a support, a plurality of pivoted clamps, a rotatable member, a plurality,

the fluid motors, and a set-screw for moving the piston of the compressor, said motors being adapted to be moved as a unit out of operative engagement with the clamps when the rotatable member is rotated through a predetermined angle.

6, In a clamping mechanism, a support, a movable clamping element on the support for clamping a member to the support, a rotatable member, and fluid operated means carried by and movable with the rotatable member'and adapted vto be connected with the clamping element, for

applying pressure to said element, said fluid operated means being ,movable out of operative relation with the clamping elementby rotation of the rotatable member whereby the member to be clamped may readily be inserted and removed.

'7. In a clamping mechanism, a plurality of separate clamps each embodying a movable element, the movable element of each clamp being capable of movement independently of movement of the movable elements of other clamps,

a movable member, fluid motors for, operating the movable elements of the clamps, there being a motor for each clamp and said motors being mounted on the movable member, said motors being operativelydisconnected from the movable elements by movement of the movable member, and a fluid compressor in communication-with the motors for operating said motors simultane- CYRIL M. ANDREWS. 

